The model of defense gene expression induced by signaling molecule β-ocimene
The model of defense gene expression induced by signaling molecule β-ocimene
复制标题
DOI：
10.1360/982004-356
复制
发表时间：
2004-12
影响因子：
--
通讯作者：
Chunlin Liu;Y. Ruan;C. Guan
中科院分区：
文献类型：
--
作者：
Chunlin Liu;Y. Ruan;C. Guan
β-罗勒烯（β-ocimene）是近年来发现的一种植物通讯信号分子。它在自然界中有两种异构形式：顺式-β-罗勒烯和反式-β-罗勒烯。据报道，玉米、棉花、利马豆、马铃薯、烟草、拟南芥、地中海松等植物在被节肢动物取食后均能释放出β-罗勒烯，表明β-罗勒烯是昆虫诱导的挥发物中的重要功能成分。目前已知β-罗勒烯可以诱导离体叶片中与水杨酸相关的防御基因的表达。但β-罗勒烯的许多问题，如β-罗勒烯是否能诱导完整植株中防御基因的表达，它在防御基因的表达模式中扮演什么样的角色等，都是未知的。为了研究这两个问题，我们以完整的拟南芥植株为试材，以水杨酸（SA）信号通路的标志基因PR 1和茉莉酸（JA）信号通路的标志基因PDF 1. 2为探针，采用北方杂交和杂交技术检测两个基因的转录本。北方杂交结果表明：（1）β-罗勒烯能够诱导防御基因的表达，这意味着β-罗勒烯能够诱导完整植株中防御基因的表达。(ii)顺式-β-罗勒烯和反式-β-罗勒烯两种异构体诱导防御基因表达的模式不同。对于反式-β-罗勒烯，随着其浓度的增加，在开始时，PR 1和PDF1.2基因的转录量增加。当其浓度为5 μmol/L时，转录量达到最大。当反式-β-罗勒烯浓度高于5 μmol/L时，PR 1和PDF1.2基因的转录量下降（图1（a）和（B））。对于顺式-β-罗勒烯，随着其浓度的增加，PR 1和PDF1.2的转录量不断增加（图1（c）和（d））。在自然状态下，食草动物饲养的猫释放的挥发物中的β-罗勒烯
β-ocimene, a kind of monoterpene, was found recently as a plant communication signal molecule. It has two isomeric forms in nature: cis-β-ocimene and trans-βocimene. According to recent reports, all investigated plants, such as corn, cotton, lima bean, potato, tobacco, arabidopsis, and Mediterranean pine, could release the chemical component β-ocimene after fed by arthropod herbivores, suggesting that β-ocimene is an important functioal component in the herbivore-induced volatile. Nowadays, we know that β-ocimene can induce the expression of defense genes relative to salicylic acid in detatched leaves. But many problems of β-ocimene, for example, whether β-ocimene can induce the defense gene expression in intact plants, what role it can play in the expression model of defense genes, are elusive. To investigate the two problems, we used intact arabidopsis plants as test materials, the fragment of PR1 gene (a symbol of salicylic acid (SA) signaling pathway) and the fragment of PDF1.2 gene (a symbol of jasmonic acid (JA) signaling pathway) as probes, and Northern blot and hybrid to detect the two-gene transcript. The Northern hybrid results show that: (i) βocimene could induce defense gene expression, which means that β-ocimene can induce defense gene expression in intact plants (Fig. 1). (ii) The two isomeric forms, cis-β-ocimene and trans-β-ocimene, have different models of inducing defense gene expression. For trans-β-ocimene, with its concentration increasing, at the beginning, the transcrip quantity of PR1 and PDF1.2 genes increased. When its concentration was 5 μmol/L, the transcript quantity reached the maximum. After the concentration of trans-β-ocimene was higher than 5 μmol/L, the transcript quantity of PR1 and PDF1.2 gene decreased (Fig. 1(a) and (b)). For cis-β-ocimene, with its concentration increasing, the transcrip quantity of PR1 and PDF1.2 increased continuously (Fig. 1(c) and (d)). In natural state, the β-ocimene in the volatile emitted from herbivore-fed